Universal gas burner for heating equipment



July 18, 1967 R. HEINRICH 3,333,424

UNIVERSAL GAS BURNER FOR HEATING EQUIPMENT Filed Sept. 1, 1965 2Sheets-Sheet 1 Iii-Til 'IiI'TIIIii lnvenfor: I R a 5 H6101 rick July 18,197 R. HEINRICH 3,331,424

UNIVERSAL GAS BURNER FUR HEATING EQUIPMENT Filed Sept. 1, 1965 2Sheets-Sheet lnvemor: IQZLLZL' Hi 171764 Ii [1 w United States Patent3,331,424 UNIVERSAL GAS BURNER FOR HEATING EQUIPMENT Rudolf Heinrich,Hamburg-Bahrenfeld, Germany,

assignor to Haller-Meurer-Werke A.G., Hamburg- Altona, Germany FiledSept. 1, 1965, Ser. No. 484,362 Claims priority, application Germany,Sept. 3, 1964, H 53,698 8 Claims. (Cl. 158117) ABSTRACT OF THEDISCLOSURE A universal gas burner for gas heating equipment mainlycomprising a gas nozzle having an outlet end, passage meanscommunicating With the nozzle at a location spaced from the outlet endfor feeding gas into the nozzle, a mixing tube having an inlet endsubstantially aligned with the outlet end of the nozzle, combustion airinlet means communicating with the inlet end of the mixing tube, aburner tube communicating with the end of the mixing tube opposite theinlet end thereof and :being formed with a plurality of openings, andcontrol means cooperating with the nozzle, the combustion air inletmeans and the openings for controlling the flow of a mixture of gas andair through the openings, one dependent upon the other.

The present invention relates to a universal gas burner for gas heatingequipment. Such gas burners usually include a gas nozzle, an inlet forthe combustion air, a mixing tube, and a burner tube provided withopenings, or slots.

Such known universal gas burners have, however, the disadvantage that,when changing over to a different type of gas, it is necessary not onlyto change the gas nozzle and to vary the flow cross section for thecombustion air, but usually it is also necessary to provide anotherburner tube, with openings or slots which are adapted to the ignitionspeed of the particular type of gas used.

Apart from the fact that the time consumed for exchange of the variouscomponents of the gas burner is quite considerable, these operations canusually be carried out only by a skilled mechanic.

It is one object of the present invention to provide a universal gasburner which can be adapted for use with a particular type of gas in anexpedient manner and without requiring any tools or particular skill.

It is a further object of the present invention to provide a universalgas burner of the aforementioned type which can be quickly adapted foruse of different types of gas and which can also be adjusted accordingto the desired heating effect to be produced by the gas burner.

It is an additional object of the present invention to provide for auniversal gas burner of the above-mentioned type which is composed offew and relatively simple parts so that the gas burner can bemanufactured at reasonable cost and will stand up trouble free underextended use.

With these objects in view, the universal gas burner according to thepresent invention mainly comprises a gas nozzle having an outlet end,passage means communicating with the nozzle at a location spaced fromthe outlet end thereof for feeding gas into the nozzle, a mixing tubehaving an inlet end substantially aligned with the outlet end of thenozzle, combustion air inlet means communicating with the inlet end ofthe mixing tube, a burner tube communicating with the end of the mixingtube which is opposite the inlet end thereof and which is formed with aplurality of openings, and control means cooperating with the nozzle,the combustion air inlet 3,331,424 Patented July 18, 1967 means andopenings in the burner inlet for controlling the flow of gas andcombustion air into the mixing tube and the outflow of the mixture ofgas and air through the openings, one dependent upon the other.

The control means preferably include a manually opera ble control memberfor adjusting the flow of gas through the outlet end of the nozzledepending on the type of gas used for the burner and for simultaneouslyand correspondingly also controlling the flow of combustion air into themixing tube.

In a preferred embodiment of the invention provision is made that thegas nozzle and the fresh air intake for the burner, as well as theopenings in the burner tube are each associated with a shutter ordiaphragm. The operation of the hand-control provides for a directadjustment of the shutter or diaphragm for the gas nozzle andadditionally for the corresponding adjustment of combustion air feed.

The shutter or control for the gas nozzle is preferably in the form of arotary member and the latter is formed preferably in one piece with ashutter for the combustion air feed, for which purpose the rotary memberis in the form of a cupshaped member. This cup-shaped member is providedwith openings of different size and ar ranged so that upon operation ofthe manual control the openings appropriate to the particular type ofgas selected come into working position.

The afore-mentioned shutter or control for varying the outflow crosssection of the burner tube is also indirectly operated from theaforementioned manual control in that after operation and starting ofthe gas burner equipment the heat produced according to the adjustmentof the aforementioned shutter controlling the flow of gas and combustionair into the mixing tube will influence a thermostat or thermallyresponsive device which adjusts, through a regulator the shuttersarranged in the burner tube and thereby the outflow of a mixture of gasand combustion air from the latter.

Preferably, the aforementioned regulator cooperates with a double-armedlever, one arm of which cooperates with a spring loaded nozzle needlefor the nozzle and the other arm of which acts through an adjusting rodon the shutter in the burner tube.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1 is a partially sectioned side view of a universal gas burneraccording to the present invention;

FIG. 2 is a cross section taken along the line 11-11 of FIG. 1;

FIG. 3 is a partial, partially sectioned view of a burner tube andshowing a modified control arrangement for controlling the outflowthrough the openings of the burner tube; and

FIGS. 4 and 5 are partial views showing different control arrangements.

Referring now to the drawings, and more particularly to FIG. 1 of thesame, it will be seen that the universal gas burner according to thepresent invention includes a gas nozzle 2 with which passage means inform of a tube 1 communicate at a location spaced from the outlet end ofthe nozzle for feeding gas into the latter. The nozzle 2 together withpipe 1 are supported in a casing 4 formed with an opening 5 throughwhich combustion air may pass into the casing 4. The casing 4 servesalso to support shutter means 6, 7 in form of a cup-shaped 3 member forrotation about its axis. As can be seen from FIG. 1, the casing 4 isprovided with cylinder portion in which the cup-shaped rotary member 6,7 is housed with the peripheral wall 7 of the cup-shaped rotary memberengaging the peripheral wall of the cylindrical portion of the housing.The end wall 6 of the rotary member facing the corresponding wall of thecylindrical portion of the housing in front of the outlet end of thenozzle 2 is formed with a plurality of apertures 18 therethrough havingrespectively different size and being arranged spaced from each otheralong a circle coaxial with the turning axis of the rotary member andhaving a radius equal to the distance between the axis of the nozzle andthe axis of the rotary member. The peripheral wall 7 of the rotarymember is likewise formed with a plurality of apertures 19 therethroughwhich have respectively different size, and which are spaced from eachother according to the spacing of the apertures 18.

A shaft 9 connected to the end wall 6 of the rotary member, and mountedfor rotation about its axis in the manner as shown in FIG. 2, isprovided at its outer end extending beyond the casing 4 with a knob 8 sothat by turning the knob 8 the rotary member may be turned about itsaxis to align an aperture 18 of selected size with an opening in thewall of the cylindrical portion of the housing located in front of theoutlet end of the nozzle 2 and to align at the same time a correspondingaperture 19 with an opening 20' formed in the peripheral wall of thecylindrical housing portion so that gas according to the selectedaperture 18 may flow into the interior of the rotary cup-shaped member,while simultaneously combustion air may flow through the opening 5, theopening 20 and the selected aperture 19 into the interior of the rotarymember.

A mixing tube 11 extends with an end portion thereof in the rotarymember 6, 7 in such a manner that the inlet end of the mixing tube 11 isaligned with and spaced from the outlet end of the nozzle 2, so that gasemanating from the outlet end of the nozzle will pass into the inlet endof the mixing tube 11 and thereby suck combustion air through openingsand 20 and through the aperture 19 aligned with the opening 20 into themixing tube 11. The mixing tube 11 may be supported in a manner notshown in the drawing and the portion extending into the rotary membersupports a plate, as shown in FIG. 2, which closes the open end of thecup-shaped member 6, 7 and which carries also a bearing for the shaft 9.Additional bafiles may be provided, not shown in the drawing, to preventany gas emanating from the outlet end of the nozzle 2 to pass throughaperture 19 and opening 20 into the interior of the housing 4 and fromthere through the opening 5 to the atmosphere. A burner tube 10 inintegrally formed or fixedly and gas-tightly connected to the end of themixing tube 11 which is opposite the inlet end thereof, and the burnertube 10 may, as shown in FIG. 1, extend at right angle to the mixingtube 11. The burner tube 10- is provided in known manner with openings12 which are preferably of slot-like form and the open cross section ofwhich can be varied according to the ignition speed of the particulartype of gas used. For this purpose a shutter 21 is provided within theburner tube 1%), as shown in FIGS. 1 and 2, and the shutter 21 shown inthese two figures is constructed as a rotary member and mounted on ashaft 22 which is arranged coaxial with the axis of the burner tube 10and mounted therein in the manner as shown for rotation about its axis.

Rotation of the shaft 22 is produced by a pinion 28 fixed to the upperend of the shaft 22 and meshing with a rack 29 fixed to one end of a rod17 mounted for reciprocation in longitudinal direction in two bearingsas shown in FIG. 1. The other end of the rod 17 is connected to one endof one arm of a double armed lever 16 which is pivotally mountedintermediate its ends.

in FIG. 1

4 The end of the other arm of the double armed leved 16 engages a springloaded needle valve member 3 located in the nozzle 2 movable toward andaway from the outlet end thereof so as to control the flow of gasthrough V the outlet end of the nozzle. The lever 16 may be turned aboutits pivot axis, as shown in FIG. 1, by means of a temperature regulatingdevice or moving means 13 which in turn is controlled by temperaturesensing means in the nature of a thermostat 14. The device 13 isconnected to one end of the rod 15, the other end of which is connectedto the double armed lever adjacent pivot axis.

The specific construction of the temperature sensing means and of thedevice 13 does not form part of the present invention and any well knowntemperature sensing means and moving means 13 connected thereto may beused which will cause during variation of the temperature sensed by thetemperature sensing means 14 movement of the rod 15 connected to themoving means 13 in one or the other direction.

The operation of the lever 16 is effected dependent on the adjustment ofthe shutter means 6, 7 operated by means of the manual control 8 andproceeds in such a manner that for instance an adjustment of the shutter6, 7 for one kind of gas with a higher heating value operates the device13, after the heating equipment has been brought into operation, throughthe lever 16 in such a manner that the flow section of the openings 12in the burner tube It) is reduced by reason of the shutter 21 and at thesame time by shifting the spring loaded needle valve member 3 relativeto the outlet end of the nozzle 2 to thus reduce the. gas flow throughthe nozzle.

It is also possible to effect common operation of the shutter 21 and theneedle valve 3 by manually operable moving means and such an arrangementis shown in FIG. 4. As shown in FIG. 4, the manually operable movingmeans includes a disc 23 turnably mounted about its axis on anappropriate support, a gear ring 24 coaxially fixed in any suitablemanner, not shown in FIG. 4, to the disc for rotation therewith, apinion 25 meshing with the gear ring 24 and provided with a hub formedwith a screw thread which engages a corresponding thread 26 on the rod15, which, in turn is connected to one arm of the double-armed lever 16.Turning of the disc 23 about its axis in one or the other direction willbe transmitted to the gear ring 24 and to the pinion 25 to result inaxial displacement of the rod 15 in the one or the other direction tothereby adjust the position of the needle valve member 3 and theposition of the shutter 21 in the burner tube 10. 0f course, the pinion25 is held in a support, in a manner not shown in FIG. 4, againstshifting in axial direction. The disc 23 is preferably provided withgraduatons of the outer periphery thereof which cooperate with astationary pointer on the support so that the position of the disc 23can be easily ascertained.

Instead of providing manually operable means for shifting the rod 15 toadjust thereby the position of the needle valve 3 and the shutter 21, itis also possible to shift the rod 15 by means of a motor and such anarrangement is shown in FIG. 5. As shown in FIG. 5, an electromo-tor 27drives a pinion 30 fixed to the motor shaft and the pinion 30 mesheswith a gear 31 having a hub provided with an inner screw thread andmeshing with a corresponding thread 26 on the rod 15. Operation of themotor 27 that is, starting, stopping, and reversing of the motor may beeffected in a known manner from a thermostatic device, not shown in FiG.5, or operation of the motor 27 may also be manually controlled byappropriate switches.

FIG. 3 shows a further modification .in which an axially movable shutter28 is provided in the burner tube for varying the open cross section ofthe openings or slots 12 formed in the burner tube 10. The axiallymovable shutter 28 is provided with a plurality of spaced slots 31corresponding in size substantially to the slots 12 in the burner tubeand which are spaced from each other in axial direction according to thespacing of the slots 12. In this case, the rod 17 connected at one endthereof to the double-armed lever 16 as shown in FIG. 1, is connected atits other end to one arm of a belt crank 29, the other arm of which isconnected in the manner as shown in FIG. 3, to the upper end of the rod30, the lower end of which carries the shutter 28 fixedly connectedthereto.

It will be seen that the universal gas burner according to the presentinvention can be adjusted not only in a very simple manner for adifferent sort of gas, but that also the regulating range of the burneris substantially increased so that practically any useful type ofheating gas can be employed.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofuniversal gas burners differing from the type described above.

While the invention has been illustrated and described as embodied inuniversal gas burner, it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madewithout departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various ap lications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet end; passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas into said nozzle; a mixing tube having an inlet endsubstantially aligned With said outlet end of said nozzle; combustionair inlet means communicating with said inlet end of said mixing tube; aburner tube communicating with the end of said mixing tube opposite saidinlet end thereof and being formed with a plurality of openings; andcontrol means cooperating with said nozzle, said combustion air inletmeans, and said openings for controlling the flow of gas and combustionair into said mixing tube and the outflow of a mixture of gas and airthrough said openings, one dependent upon the other, said control meansincluding three shutters respectively coordinated with said outlet endof said nozzle, said combustion air inlet means, and said openings ofsaid burner tube, the shutters coordinated with said outlet end of saidnozzle and with said combustion air inlet means being integral with eachother and being formed by a cup-shaped rotary member having a front wallfacing said outlet end of said nozzle and a peripheral wall facing saidcombustion air inlet means, said front wall and said peripheral wallbeing each formed with openings of different size respectively adaptedto be aligned with said outlet end of said nozzle and said combustionair inlet means by turning said cupshaped rotary member about its axis.

2. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet end; passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas into said nozzle; a mixing tube having an inlet endsubstantially aligned with said outlet end of said nozzle; combustionair inlet means communicating with said inlet end of said mixing tube; aburner tube communicating with the end of said mixing tube opposite saidinlet end thereof and being formed with a plurality of openings; firstcontrol means cooperating with said outlet end of said nozzle and withsaid combustion air inlet means for adjusting the flow of gas into saidmixing tube and for simultaneously adjusting flow of combustion air intosaid mixing tube corresponding to the adjusted flow of gas thereinto;second control means cooperating with said nozzle and said openings ofsaid burner tube for further controlling flow of gas from said nozzleinto said mixing tube and for simultaneously and correspondinglyadjusting outflow of a mixture of gas and combustion air through saidopenings of said burner tube, said second control means including aneedle valve member located in said nozzle and being movable toward andaway from said outlet end thereof for varying the free cross section ofsaid outlet end, and shutter means in said burner tube movable relativeto said openings for varying the free cross section thereof; temperaturesensing means; and operating means cooperating with the temperaturesensing means and operatively connected to said needle valve and saidshutter means for moving said needle valve relative to said outletopening of said nozzle and for simultaneously moving said shutter meansrelative to said openings of said burner tube.

3. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet end; passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas into said nozzle; a mixing tube having an inlet endsubstantially aligned with said outlet end of said nozzle; combustionair inlet means communicating with said inlet end of said mixing tube; aburner tube communicating with the end of said mixing tube opposite saidinlet end thereof and being formed with a plurality of openings; firstcontrol means cooperating with said outlet end of said nozzle and withsaid combustion air inlet means for adjusting the flow of gas into saidmixing tube and for simultaneously adjusting flow of combustion air intosaid mixing tube corresponding to the adjusted flow of gas thereinto;second control means cooperating with said nozzle and said openings ofsaid burner tube for further controlling flow of gas from said nozzleinto said mixing tube and for simultaneously and correspondinglyadjusting outflow of a mixture of gas and combustion air through saidopenings of said burner tube, said second control means including aneedle valve member located in said nozzle and being movable toward andaway from said outlet end thereof for varying the free cross section ofsaid outlet end, and shutter means in said burner tube movable relativeto said openings for varying the free cross section thereof; temperaturesensing means; and operating means including a double-armed leverpivotally mounted intermediate its ends, and having one arm operativelyconnected to said needle valve member and the other to said shuttermeans in said burner tube, and moving means cooperating with saidtemperature sensing means for turning said lever about its pivot axisdepending on the temperature sensed by said temperature sensing means tothereby adjust the position of said needle valve member in said nozzleand the position of said shutter means relative to said openings in saidburner tube dependent on the temperature sensed by said temperaturesensing means.

4. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet end; passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas into said nozzle; a mixing tube having an inlet endsubstantially aligned with said outlet end of said nozzle; combustionair inlet means communicating with said inlet end of said mixing tube; aburner tube communicating with the end of said mixing tube opposite saidinlet end thereof and being formed with a plurality of openings; firstcontrol means cooperating with said outlet end of said nozzle and withsaid combustion air inlet means for adjusting the flow of gas into saidmixing tube and for simultaneously adjusting flow of combustion air intosaid mixing tube corresponding to the adjusted How of gas thereinto;second control means cooperating with said nozzle and said openings ofsaid burner tube for further controlling flow of gas from said nozzleinto said mixing tube and for simultaneously and correspondinglyadjusting outflow of a mixture of gas and combustion air through saidopenings of said burner tube, said second control means including aneedle valve member located in said nozzle and being movable toward andaway from said outlet end thereof for varying the free cross section ofsaid outlet end, and shutter means in said burner tube movable relativeto said openings for varying the free cross section thereof; temperaturesensing means; and operating means including a double-armed pivotallymounted intermediate its ends, and having one arm operatively connectedto said needle valve member and the other to said shutter means in saidburner tube, and manually operable moving means operatively connected tosaid lever for turning the latter about its pivot axis to thereby adjustthe position of said needle valve member in said nozzle and the positionof said shutter means relative to said openings in said burner tube.

5. A universal gas burner as set forth in claim 4, wherein said manuallyoperable moving means include a disc turnable about an axis, a gear ringcoaxially fixed to said disc, a pinion meshing with said gear ring andhaving a threaded hub, and a rod operatively connected at one end to onearm of said lever and having spaced from said one end a threaded portionthreadingly engaging said hub of said pinion to be axially moved uponrotation of said pinion.

6. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet end; passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas into said nozzle; a mixing tube having an inlet endsubstantially aligned with said outlet end of said nozzle; combustionair inlet means communicating with said inlet end of said mixing tube; aburner tube communicating with the end of said mixing tube opposite saidinlet end thereof and being formed with a plurality of openings; firstcontrol means cooperating with said outlet end of said nozzle and withsaid combustion air inlet means for adjusting the flow of gas into saidmixing tube and for simultaneously adjusting fiow of combustion air intosaid mixing tube corresponding to the adjusted flow of gas thereinto;second control means cooperating with said nozzle and said openings ofsaid burner tube for further controlling flow of gas from said nozzleinto said mixing tube and for simultaneously and correspondinglyadjusting outflow of a mixture of gas and combustion air through saidopenings of said burner tube, said second control means including aneedle valve member located in said nozzle and being movable toward andaway from said outlet end thereof for varying the free cross section ofsaid outlet end, and shutter means in said burner tube movable relativeto said openings for varying the free cross section thereof; temperaturesensing means; and operating means including a double-armed pivotallymounted intermediate its ends, and having one arm operatively connectedto said needle valve member and the other to said shutter means in saidburner tube, and motor means operatively connected to said lever forturning the latter about its pivot axis to thereby adjust the positionof said needle valve member in said nozzle and the posi- 7 tion of saidshutter means relative to said openings in said burner tube.

7. A universal gas burner for gas heating equipment comprising, incombination, a gas nozzle having an outlet 7 end; gas passage meanscommunicating with said nozzle at a location spaced from said outlet endfor feeding gas through said second opening; a burner tube communicatingwith the end of said mixing tube opposite said inlet end thereof andbeing formed with a plurality of openings spaced from each other; acup-shaped member in said casing and having an end wall abutting againstsaid side Wall of said casing and a peripheral wall engaging with theouter surface thereof said annular wall of said casing, said cupshapedmember being arranged in said casing turnably about a turning axisspaced from said outlet end of said nozzle and being formed in said endwall with a first plurality of apertures of different size arrangedspaced from each other along a circle coaxial with said turning axis andin said peripheral wall with a second plurality of apertures ofdifferent size respectively spaced from each other according to thespacing of said first plurality of apertures; manually operable meansconnected to said cup-shaped member for turning the latter about saidturning axis so as to align one aperture of selected size of said firstplurality of apertures with said opening in said side wall of saidcasing and a corresponding aperture of said second plurality ofapertures with said opening of said annular wall of said casing; aneedle valve in said nozzle movable toward and away from said outletend; shutter means in said burner tube and movable relative to saidopenings for adjusting the free cross section thereof; temperaturesensing means; and operating means cooperating with said temperaturesensing means and operatively connected to said needle valve and saidshutter means for adjusting the position of said needle valve relativeto said outlet opening of said nozzle and the position of said shuttermeans relative to said openings of said burner tube depending on thetemperature sensed by said temperature sensing means.

8. A universal gas burner as set forth in claim 7, wherein said shuttermeans in said burner tube is a rotary member angularly adjustable aboutan axis coaxial with said burner tube, and wherein said operating meansinclude a double-armed lever pivoted about a pivot axis intermediate itsends, a rod mounted for reciprocation in longitudinal direction andbeing operatively connected at one end thereof to one end of one arm ofsaid lever and carrying on the other end thereof a rack, a pinioncoaxial with and operatively connected to said rotary memher and meshingwith said rack, moving means cooperating with said temperature sensingmeans and operatively con-.

nected to said lever adjacent said pivot axis for pivoting said leverabout said axis depending on the temperature sensed by said temperaturesensing means, and connecting means connecting the other end of saidlever to said needle FREDERICK L. MATTESO-N, In, Primary Examiner.

H. B. RAMEY, Assistant Examiner.

1. A UNIVERSAL GAS BURNER FOR GAS HEATING EQUIPMENT COMPRISING, INCOMBINATION, A GAS NOZZLE HAVING AN OUTLET END; PASSAGE MEANSCOMMUNICATING WITH SAID NOZZLE AT A LOCATION SPACED FROM SAID OUTLET ENDFOR FEEDING GAS INTO SAID NOZZLE; A MIXING TUBE HAVING AN INLET ENDSUBSTANTIALLY ALIGNED WITH SAID OUTLET END OF SAID NOZZLE; COMBUSTIONAIR INLET MEANS COMMUNICATING WITH SAID INLET END OF SAID MIXING TUBE; ABURNER TUBE COMMUNICATING WITH THE END OF SAID MIXING TUBE OPPOSITE SAIDINLET END THEREOF AND BEING FORMED WITH A PLURALITY OF OPENINGS; ANDCONTROL MEANS COOPERATING WITH SAID NOZZLE, SAID COMBUSTION AIR INLETMEANS, AND SAID OPENINGS FOR CONTROLLING THE FLOW OF GAS AND COMBUSTIONAIR INTO SAID MIXING TUBE AND THE OUTFLOW OF A MIXTURE OF GAS AND AIRTHROUGH SAID OPENINGS, ONE DEPENDENT UPON THE OTHER, SAID CONTROL MEANSINCLUDING THREE SHUTTERS RESPECTIVELY COORDINATED WITH SAID OUTLET ENDOF SAID NOZZLE, SAID COMBUSTION AIR INLET MEANS, AND SAID OPENINGS OFSAID BURNER TUBE, THE SHUTTERS CO-